Baseballsurfmom
I just saw this post, so I am sorry I am so late in responding. At this point, you probably have worked with your son's doctors to determine whether surgery or rest is the appropriate course of action. Nevertheless, I thought I would tell you about our experience in case you are still working through this. My son developed OCD of the elbow when he was 12 years old (he is now 16). He was (and still is!) a pitcher and shortstop. He had pain in both his elbow and shoulder and we went to the orthopedic doctor, who diagnosed OCD of the elbow (his shoulder was fine). We ended up going to a specialist in Boston who sees many of these cases (in fact, right around the same time my son was diagnosed, three other boys he played baseball with were diagnosed with the same condition and saw the same doctor). Luckily, the fragment had not broken off in my son's elbow (and he did not appear to have lost any range of motion) and he was told to completely rest the arm for 6 months. He was diagnosed in September, so he just rested his arm through the winter and, in March, he began an interval throwing program. He had no pain during the throwing program and he worked back into playing first base and then shortstop after a couple months. While the doctor advised that our son could work back to pitching, the doctor seemed to prefer the more conservative approach of holding off from pitching for a while. We decided to follow the conservative approach and did not have our son pitch for the majority of the season. At the very end of the season (August), we had him pitch just a couple innings during a playoff game and he had no issues. That winter, he had some pitching lessons to improve his mechanics and he has been pitching ever since with no problems (knock wood!).
I should tell you that the other players who had OCD had more serious cases (I think they all continued to pitch and throw after experiencing pain and loss of range of motion and clicking of the elbow, while my son spoke up pretty quickly after he began experiencing the pain and he stopped throwing pretty quickly) and they all ended up having surgery. Two of them returned to baseball and to catching. One of them also pitched on occasion and continued to do so. I have not talked to them in a few years, so I don't know if they have recurring issues at all.
I hope that helps (even at this late date)!